Seneca City Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Seneca City Park clear sky chart from 2005-11-05 to 2017-09-18.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.
Observation TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(no limit)Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
41%
15936
22%
47064
13%
15889
50%
15889
32%
28117

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 15thNight
31%
900
22%
2327
8%
895
41%
895
31%
1502
January16th to endNight
27%
960
25%
2496
8%
960
40%
960
33%
1570
February1st to 15thNight
26%
879
15%
2288
4%
875
32%
875
23%
1632
February16th to endNight
28%
666
24%
1928
7%
666
41%
666
30%
1190
March1st to 15thNight
33%
548
21%
1988
12%
548
45%
548
25%
1130
March16th to endNight
25%
576
16%
2112
8%
576
35%
576
18%
1371
April1st to 15thNight
29%
539
20%
1887
12%
539
43%
539
26%
1090
April16th to endNight
29%
540
21%
1631
13%
540
42%
540
23%
1072
May1st to 15thNight
37%
539
18%
1620
14%
539
44%
539
25%
1057
May16th to endNight
44%
563
17%
1684
11%
561
51%
561
31%
1022
June1st to 15thNight
55%
540
19%
1491
9%
540
60%
540
40%
858
June16th to endNight
59%
540
23%
1533
12%
540
65%
540
52%
774
July1st to 15thNight
64%
510
16%
1530
13%
510
66%
510
40%
859
July16th to endNight
72%
564
24%
1594
23%
531
76%
531
44%
847
August1st to 15thNight
74%
539
22%
1610
25%
536
77%
536
41%
874
August16th to endNight
67%
573
27%
1761
29%
573
71%
573
40%
951
September1st to 15thNight
55%
540
23%
1913
22%
540
62%
540
32%
1052
September16th to endNight
56%
501
29%
1848
24%
501
66%
501
37%
929
October1st to 15thNight
43%
621
27%
1941
19%
621
49%
621
31%
1123
October16th to endNight
39%
704
28%
2112
13%
704
50%
704
38%
1149
November1st to 15thNight
42%
834
29%
2234
13%
834
53%
834
42%
1245
November16th to endNight
34%
900
25%
2439
9%
900
45%
900
34%
1452
December1st to 15thNight
28%
900
19%
2520
7%
900
38%
900
26%
1645
December16th to endNight
29%
960
23%
2577
9%
960
41%
960
27%
1723

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

Occurrence of each ForecastData
Points
Cloud CoverDay
10%6%25%42445%7%45%
47715
Night
9%5%2442345%7%50%
47260
Cloud CoverDay
10%6%25%42445%7%45%
47713
Night
9%5%2442345%7%50%
47260
TransparencyDay
37%6%13%24%15%2
47413
Night
33%5%13%26%17%3
47065
SeeingDay
12%7%28%31%16%3
5947
Night
12%8%33%33%11%
15938

By Month

Percentage Cloud Cover SW (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
9%5%26%5%45%347%45%
1611
16th to endDay
9%8%37%5%24447%42%
1728
February1st to 15thDay
11%8%5%8%5%2435%6%38%
1575
16th to endDay
9%8%26%5%24349%42%
1557
March1st to 15thDay
10%10%35%4345%46%40%
1971
16th to endDay
15%10%47%5%24346%34%
2112
April1st to 15thDay
13%8%35%5%24345%43%
2060
16th to endDay
19%8%25%425%45%7%34%
2327
May1st to 15thDay
13%7%36%6%35%46%6%37%
2331
16th to endDay
13%7%25%5%25%45%8%39%
2430
June1st to 15thDay
9%5%145%3445%7%48%
2463
16th to endDay
5%2233345%7%9%51%
2419
July1st to 15thDay
8%314435%6%7%9%44%
2340
16th to endDay
5%3245%245%6%9%49%
2466
August1st to 15thDay
6%325%5%25%5%6%8%47%
2340
16th to endDay
8%32443346%7%50%
2441
September1st to 15thDay
10%4145%35%45%6%48%
2046
16th to endDay
7%5%25%423446%53%
1837
October1st to 15thDay
12%42332335%6%52%
1678
16th to endDay
10%5%13322336%55%
1760
November1st to 15thDay
8%413313346%59%
1622
16th to endDay
10%7%35%423445%49%
1518
December1st to 15thDay
10%8%37%6%3435%7%38%
1440
16th to endDay
12%9%48%5%34446%37%
1643
January1st to 15thNight
7%6%36%4345%47%47%
2327
16th to endNight
8%6%36%413445%50%
2496
February1st to 15thNight
10%9%47%6%25%446%37%
2278
16th to endNight
8%6%25%43445%7%46%
1928
March1st to 15thNight
9%6%25%42445%6%49%
1988
16th to endNight
16%9%3442445%7%37%
2112
April1st to 15thNight
12%6%245%2335%6%49%
1887
16th to endNight
18%6%25%323446%42%
1631
May1st to 15thNight
13%6%345%34446%42%
1619
16th to endNight
11%42341446%9%47%
1683
June1st to 15thNight
6%313424449%54%
1491
16th to endNight
321132446%9%61%
1533
July1st to 15thNight
6%32442447%8%51%
1620
16th to endNight
421343446%9%55%
1702
August1st to 15thNight
321342446%8%56%
1620
16th to endNight
6%324323346%58%
1761
September1st to 15thNight
8%42442435%7%52%
1913
16th to endNight
8%313323446%59%
1848
October1st to 15thNight
13%5%23323336%52%
1941
16th to endNight
10%6%13212235%59%
2112
November1st to 15thNight
6%5%1231335%7%58%
2234
16th to endNight
10%5%23313445%54%
2439
December1st to 15thNight
11%7%35%5%3435%5%45%
2520
16th to endNight
12%10%45%412345%44%
2577

Percentage Cloud Cover SE (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
9%5%26%5%45%347%44%
1611
16th to endDay
9%8%36%5%23447%42%
1728
February1st to 15thDay
11%8%5%8%5%2435%6%38%
1575
16th to endDay
9%8%36%424348%42%
1557
March1st to 15thDay
10%10%35%4345%46%40%
1971
16th to endDay
16%10%47%5%34346%34%
2110
April1st to 15thDay
13%7%35%5%24335%43%
2060
16th to endDay
19%8%35%415%45%7%34%
2327
May1st to 15thDay
12%7%36%6%35%5%5%6%37%
2331
16th to endDay
13%6%25%5%3435%8%39%
2430
June1st to 15thDay
8%5%145%2445%7%48%
2463
16th to endDay
5%2143345%6%10%50%
2419
July1st to 15thDay
8%314435%6%6%10%44%
2340
16th to endDay
5%4144345%6%9%49%
2466
August1st to 15thDay
6%325%5%35%5%7%7%47%
2340
16th to endDay
8%4245%2445%7%49%
2441
September1st to 15thDay
10%4135%34446%48%
2046
16th to endDay
7%425%3345%46%52%
1837
October1st to 15thDay
12%42332335%6%52%
1678
16th to endDay
10%5%14323336%55%
1760
November1st to 15thDay
8%413313346%58%
1622
16th to endDay
10%7%35%423445%49%
1518
December1st to 15thDay
10%8%46%6%3345%7%38%
1440
16th to endDay
12%9%48%433446%36%
1643
January1st to 15thNight
7%6%36%4335%47%47%
2327
16th to endNight
8%6%36%423345%50%
2496
February1st to 15thNight
10%9%47%6%35%446%37%
2278
16th to endNight
8%6%25%43445%7%46%
1928
March1st to 15thNight
9%6%2442435%5%49%
1988
16th to endNight
16%9%3442445%6%37%
2112
April1st to 15thNight
12%6%145%23346%49%
1887
16th to endNight
17%6%24423446%42%
1631
May1st to 15thNight
13%6%345%3445%6%42%
1619
16th to endNight
11%42341445%9%47%
1683
June1st to 15thNight
6%31343435%9%54%
1491
16th to endNight
321132346%10%60%
1533
July1st to 15thNight
5%32441446%8%52%
1620
16th to endNight
421343446%10%54%
1702
August1st to 15thNight
32134245%5%9%56%
1620
16th to endNight
6%32432335%6%57%
1761
September1st to 15thNight
8%424423447%52%
1913
16th to endNight
8%313423346%59%
1848
October1st to 15thNight
13%5%23323336%52%
1941
16th to endNight
10%6%13212235%59%
2112
November1st to 15thNight
7%5%1221435%6%58%
2234
16th to endNight
10%5%23323445%53%
2439
December1st to 15thNight
11%8%35%5%3335%5%45%
2520
16th to endNight
13%9%46%312346%43%
2577

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
39%414%27%12%1
1612
16th to endDay
41%5%16%22%12%1
1728
February1st to 15thDay
46%5%15%21%8%1
1576
16th to endDay
40%6%12%24%15%1
1557
March1st to 15thDay
43%6%11%22%14%1
1971
16th to endDay
50%5%12%20%8%1
2112
April1st to 15thDay
43%411%22%15%
2060
16th to endDay
48%5%11%23%10%
2327
May1st to 15thDay
45%7%10%21%13%
2331
16th to endDay
42%8%14%22%11%1
2434
June1st to 15thDay
34%8%11%27%15%1
2463
16th to endDay
26%7%17%28%16%2
2419
July1st to 15thDay
33%8%15%27%13%3
2201
16th to endDay
27%7%15%29%17%2
2311
August1st to 15thDay
32%8%14%26%16%1
2326
16th to endDay
32%6%11%25%18%6%
2441
September1st to 15thDay
35%6%13%21%19%4
2046
16th to endDay
31%5%11%26%23%1
1837
October1st to 15thDay
32%5%10%24%24%3
1678
16th to endDay
31%413%25%20%4
1760
November1st to 15thDay
26%411%28%24%4
1622
16th to endDay
36%411%29%16%1
1518
December1st to 15thDay
44%5%16%22%9%
1440
16th to endDay
48%5%13%20%10%1
1643
January1st to 15thNight
36%5%15%24%17%
2327
16th to endNight
35%415%27%14%3
2496
February1st to 15thNight
47%6%12%21%11%1
2288
16th to endNight
35%5%13%24%16%4
1928
March1st to 15thNight
34%5%13%24%17%3
1988
16th to endNight
45%6%13%21%9%3
2112
April1st to 15thNight
36%410%27%19%2
1887
16th to endNight
42%5%10%24%15%
1631
May1st to 15thNight
41%6%11%22%16%1
1620
16th to endNight
32%8%18%23%15%1
1685
June1st to 15thNight
26%6%16%32%13%4
1491
16th to endNight
17%5%16%33%22%3
1533
July1st to 15thNight
26%6%15%28%18%4
1530
16th to endNight
22%6%14%32%21%2
1594
August1st to 15thNight
23%8%16%29%20%2
1610
16th to endNight
26%5%11%27%21%7%
1761
September1st to 15thNight
30%6%11%26%18%6%
1913
16th to endNight
26%5%11%28%26%3
1848
October1st to 15thNight
33%410%23%22%5%
1941
16th to endNight
28%310%29%23%4
2112
November1st to 15thNight
25%413%25%24%6%
2234
16th to endNight
31%411%29%20%2
2439
December1st to 15thNight
40%5%13%27%12%
2520
16th to endNight
42%414%24%12%2
2577

Seeing (when cloud cover <= 80%)
Color Meanings:
Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
20%12%45%16%41
90
16th to endDay
17%11%39%30%1
96
February1st to 15thDay
12%21%45%18%2
90
16th to endDay
8%18%44%17%8%2
81
March1st to 15thDay
16%18%37%25%1
90
16th to endDay
27%16%39%11%5%
96
April1st to 15thDay
18%10%36%22%11%
179
16th to endDay
24%16%31%20%6%
437
May1st to 15thDay
14%12%32%26%11%1
468
16th to endDay
17%10%33%26%8%2
517
June1st to 15thDay
8%431%31%21%3
495
16th to endDay
3435%34%17%3
495
July1st to 15thDay
9%318%40%21%5%
475
16th to endDay
6%14%44%30%3
515
August1st to 15thDay
6%116%44%26%4
493
16th to endDay
10%318%33%27%5%
481
September1st to 15thDay
6%322%41%20%4
201
16th to endDay
8%8%27%38%14%3
96
October1st to 15thDay
7%10%34%28%10%8%
90
16th to endDay
7%7%44%32%6%2
96
November1st to 15thDay
5%8%26%32%22%4
90
16th to endDay
33%12%40%10%4
90
December1st to 15thDay
15%20%44%14%23
90
16th to endDay
28%15%35%19%1
96
January1st to 15thNight
10%13%41%28%6%
900
16th to endNight
12%11%43%27%5%
960
February1st to 15thNight
14%11%40%29%4
880
16th to endNight
13%10%43%25%6%
666
March1st to 15thNight
13%12%36%29%7%
548
16th to endNight
21%12%37%22%5%
576
April1st to 15thNight
15%10%41%26%5%
539
16th to endNight
19%10%38%25%5%
540
May1st to 15thNight
14%10%32%30%10%
540
16th to endNight
13%433%35%12%
563
June1st to 15thNight
8%5%26%42%16%
540
16th to endNight
3231%46%15%
540
July1st to 15thNight
7%20%48%21%
510
16th to endNight
5%15%52%25%1
564
August1st to 15thNight
4112%52%26%2
539
16th to endNight
7%116%42%26%4
573
September1st to 15thNight
10%324%37%20%3
540
16th to endNight
7%428%38%19%2
501
October1st to 15thNight
16%6%31%31%12%1
621
16th to endNight
14%9%34%31%9%
704
November1st to 15thNight
10%11%32%33%10%
834
16th to endNight
13%13%37%27%8%
900
December1st to 15thNight
15%14%38%25%5%
900
16th to endNight
16%11%37%28%6%
960
Page generated at 2017-09-19 06:32:30. Version ac04

Copyright 2017 A. Danko


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